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Wohlfahrt M.,University of Leoben | Oberwinkler C.,University of Leoben | Tunzini S.,Georg Fischer Automotive AG | Rauscher A.,Magna Powertrain AG and Co KG | And 2 more authors.
Procedia Engineering | Year: 2010

In the present study the effect of an austempering heat treatment on the quasi-static and fatigue behaviour of ductile iron was studied. 40 mm Y-blocks were used for the investigations with the risers cut off before heat treatment. Testing specimens with as-cast (pearlitic) and austempered microstructure were taken out from two different positions of the Y-blocks. The austempering heat treatment increases tensile strength, yield strength, elongation at fracture and fatigue strength. Tensile and fatigue tests verify that the mechanical properties are lower close to the riser. This is explained by the varying microstructure in the Y-blocks. © 2010 Published by Elsevier Ltd.


Paar C.,MAGNA Powertrain AG and Co. KG | Paar C.,University of Graz | Muetze A.,University of Graz | Kolbe H.,University of Graz
IEEE Transactions on Industry Applications | Year: 2015

This paper describes a method for fast identification of the thermal behavior of vehicle integrated electric drives to propose a better understanding of electric machine design tailored to driving cycles. A simple, but satisfactorily accurate, calculation method for the estimation of machine losses, which is an input for the analytic thermal network, in the early design stage is introduced. The analytic models, which are verified using measurement data, are used for parameter and case studies for consideration of the thermal environment, with a focus on the gearbox. The first case study analyzes the influence of the gearbox on the thermal behavior of critical machine components. Aiming to use the gearbox lubricant for cooling the winding heads, an improvement of machine performance using an alternative cooling approach, which cools down the end windings, is shown in the second case study. © 1972-2012 IEEE.


Ringdorfer M.,Magna Powertrain AG and Co KG | Horn M.,Alpen Adria Universtitat Klagenfurt
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2013

The paper introduces a novel vehicle dynamics control concept based on a hybrid actuator system consisting of friction brake and traction machine. This configuration offers new degrees of freedom in the control of electric vehicles. The proposed approach is based on a cascaded control structure with an inner yaw rate loop and an outer sideslip angle feedback loop. The use of sliding mode algorithms accounts for plant uncertainties and reduces the effort for controller tuning to a minimum without neglecting the aspect of energy efficiency. With the help of selected driving maneuvers it is shown that the performance of a car equipped with the advanced stability control system is superior to a car with conventional electronic stability algorithms.


Vengudusamy B.,Ac2t Research Gmbh | Grafl A.,Ac2t Research Gmbh | Novotny-Farkas F.,OMV Austria Exploration and Production GmbH | Schofmann W.,Magna Powertrain AG and Co KG
Lubrication Science | Year: 2014

The friction behaviour of five different gear oils in rolling-sliding and pure sliding contacts and how temperature influences their friction properties were investigated. It is found that increasing temperature decreases boundary frictionwith gear oils that contain frictionmodifierswhile not for other gear oils, at all contact pressures investigated. In mixed lubrication region, temperature decreases friction at low contact pressures while increases friction at high contact pressures. The effect of slide-roll ratio on friction is significant in boundary lubrication region especially at higher temperature while less significant in mixed lubrication region at both low and high temperatures. The ranking of gear oils for friction in boundary and mixed lubrication regimes is similar both in rolling-sliding and pure sliding contacts, regardless of temperature. © 2013 John Wiley & Sons, Ltd.


Vengudusamy B.,Ac2t Research Gmbh | Grafl A.,Ac2t Research Gmbh | Novotny-Farkas F.,OMV Austria Exploration and Production GmbH | Schofmann W.,Magna Powertrain AG and Co KG
Tribology International | Year: 2013

The friction responses of five fully formulated gear oils including mineral and synthetic oils were studied. This article examines the impact of contact motion types (rolling-sliding and pure sliding) and contact pressure on boundary and mixed friction properties of the selected gear oils in MTM (minitraction machine) and SRV (Schwing-Reib-Verschleiss tribometer). Mineral oils are found to be less affected by contact pressure compared to synthetic oils. Gear oils that show adsorption appear to be less sensitive to contact motion type in mixed lubrication while behave much more sensitive in boundary lubrication regimes. The ranking of gear oils for mixed friction was similar regardless of contact motion types at low contact pressures while differ at high contact pressures. © 2013 Elsevier Ltd.


Vengudusamy B.,Ac2t Research Gmbh | Grafl A.,Ac2t Research Gmbh | Novotny-Farkas F.,OMV Austria Exploration and Production GmbH | Schofmann W.,Magna Powertrain AG and Co KG
Tribology Transactions | Year: 2014

Improving knowledge of the tribological behavior of gear oils under different operating conditions is essential to be able to design efficient lubricants for gear contacts. This article examines how surface roughness influences the friction properties of gear oils in boundary-lubricated steel-steel contacts at different temperatures and contact pressures. Stribeck curves were generated for smoother and rougher substrates. Friction in the boundary lubrication regime from Stribeck curves and the evolution of friction during prolonged rubbing were used to evaluate the abilities of additives to adsorb on steel surfaces, form tribofilms, and withstand severe operating conditions. In general, smoother substrates produce lower friction but higher wear than rougher substrates for the oils and operating conditions investigated in this study. Surface roughness has significant effects on additive adsorption and tribofilm formation at low contact pressures and negligible effects at high contact pressures. In addition, whether or not other surface-active additives present in gear oils affect the typical low friction response of friction modifiers (FMs) was investigated. The results show that severe operating conditions (pure sliding and high contact pressure) could cause disruption of FM films with some gear oils and hence do not reduce friction. In a forthcoming companion article, Part II, these Stribeck curves are used to understand the response of different gear oils in mixed lubrication with varying substrate roughnesses and to understand how tribofilms influence friction in mixed lubrication by evaluating tribofilm-generated surfaces with base oil (Vengudusamy, et al. (1)). © 2014 Copyright Taylor & Francis Group, LLC.


Ringdorfer M.,Klagenfurt University | Ringdorfer M.,Magna Powertrain AG and Co KG | Horn M.,Klagenfurt University
Proceedings of the IEEE International Conference on Control Applications | Year: 2011

A new vehicle stability control approach for electric vehicles is introduced. The proposed wheel slip controller extends the functionality of state-of-the-art electric vehicle operation strategies and closes the gap to driver assistance systems and conventional vehicle dynamics control systems. Maximum energy efficiency and driving safety can be guaranteed by coordinated control of the electrical propulsion system and the mechanical braking system. During safe vehicle operation, the controller monitors the vehicle operation unit and in case of a blocking or spinning wheel, it assures anti blocking and anti slip functionalities by coordinating mechanical brake interventions and single wheel traction motor control. The proposed controller structure is outlined and first simulation results are presented. © 2011 IEEE.


Paar C.,Magna Powertrain AG and Co. KG | Kolbe H.,Graz University of Technology | Muetze A.,Graz University of Technology
2014 IEEE Energy Conversion Congress and Exposition, ECCE 2014 | Year: 2014

We present a method for fast identification of the thermal behavior of vehicle integrated electric drives to propose a better understanding of electric machine design tailored to driving cycles. A simple, but satisfactorily accurate calculation method for the estimation of machine losses, which is an input for the analytic thermal network, in the early design stage is introduced. The analytic models, which are verified using measurement data, are used for parameter and case studies for consideration of the thermal environment with focus on the gearbox. An improvement of machine performance using an alternative cooling approach which cools down the end windings is shown in the final section of the paper. © 2014 IEEE.


Stoschka M.,University of Leoben | Thaler M.,University of Leoben | Huemer H.,Magna Powertrain AG and Co KG | Eichlseder W.,University of Leoben
Procedia Engineering | Year: 2011

Laser welded components are widely used in automotive industry enabling high quality joints with minimized heat energy input. This paper contributes to the feasible fatigue levels of disc laser welded joints made of 20MnCr5 and GJS620 using different process parameters. The fatigue behaviour of similar joints made of 20MnCr5 was also studied for two different contact conditions. The influence of the heterogeneous start and stop pilot region of the laser beam to fatigue life is also discussed. Accompanying fracture analysis detected the spot of technical crack initiation at the most stressed root surface. A high process quality for the laser welded joints was confirmed by examining both metallographic sections and the surface topography. Structural weld simulation work was performed to elucidate the local differences between the continuous seam and the overlapping laser weld pilot regions. Investigations showed that the notch stress approach with an effective radius of 0.05 mm lead to S/N-curves which generally matched the standard recommendations regarding fatigue. © 2011 Published by Elsevier Ltd.


This paper deals with the analysis of friction characteristics of wet multi plate clutches with regards to adverse drivetrain-oscillations using a suitable multidomain simulation approach. This is accomplished with the example of an AWD-vehicle architecture with front transverse engine and torque transmission to the rear axle via a hang-on AWD coupling which is hydraulically actuated by a differential-speed-sensing pump. The aim is to demonstrate the interactions of the tribological system on the vibration behavior of the drivetrain. A special focus lies on the precise description of the static and dynamic friction coefficients. In addition, influences of various drivetrain parameters are discussed. The validation is based on selected vehicle measurements.

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